Many people have persistent physical complaints, such as dizziness or pain, that don't appear to be symptoms of a medical condition.
They are sometimes known as "medically unexplained symptoms" when they last for more than a few weeks, but doctors can't find a problem with the body that may be the cause.
This doesn't mean the symptoms are faked or "all in the head" – they're real and can affect your ability to function properly.
Not understanding the cause can make them even more distressing and difficult to cope with.
When mystery symptoms seem to be caused by problems in the nervous system but you don't have a specific neurological condition, doctors may refer to your symptoms as a ‘functional neurological disorder’.
Examples of such symptoms include:
Medically unexplained symptoms are common, accounting for up to 45% of all GP appointments and half of all new visits to hospital clinics in the UK.
Treating an associated psychological problem can often relieve the physical symptoms.
For others, the symptoms may be part of a poorly understood syndrome, such as:
The fact that doctors are unable to find a condition causing these symptoms isn't unusual in medicine, and it doesn't mean that nothing can be done to help you.
Your GP will aim to rule out all the possible conditions that might be causing your symptoms. You may have a thorough physical examination and blood tests.
It's important to consider whether any medication you're taking may be causing your symptoms – for example, taking painkillers long term can lead to painkiller headaches.
Your GP should also investigate whether you might have an associated problem, such as depression or anxiety. Physical symptoms can cause depression and anxiety, and these can in turn make the physical symptoms worse, creating a vicious circle.
You should tell your GP:
There are a number of things you can do yourself that may help.
You and your GP may identify some lifestyle changes and goals that you both think will help relieve your symptoms, such as regular physical activity and better rest (see below).
You may be referred for a talking therapy, such as cognitive behavioural therapy (CBT). The aim of CBT is to help you to manage your symptoms by enabling you to understand links between your symptoms, worries, feelings and how you cope.
If your symptoms seem to be caused by a problem with the nervous system, you may be referred to a neurologist (a specialist in disorders of the nervous system).
The neurologist may refer you for psychotherapy but will also consider other therapy options, such as physiotherapy or occupational therapy .
Medication such as antidepressants can be helpful, even if you're not depressed. However, medication isn't always the answer – painkillers or sedatives, for example, may lead to dependence. The possible benefits of medication always need to be weighed against the potential side effects.
If you think you have an underlying condition that's been missed by your doctor, you can ask for a second opinion.
There are things you can do to improve or even relieve some physical symptoms, such as taking regular exercise and managing stress.
Regular exercise will help keep you fit and many people find that it also boosts their mood (read about exercise for depression). How much exercise you should do will depend on your current health and capabilities.
Your body has a remarkable ability to recover and there's a good chance that your symptoms will improve in time, even without any specific treatment.
Unexplained symptoms tend to be more common among: